High density optical recording systems which may be used for recording and playing back information are known in the prior art. For example, in U.S. Pat. No. 4,097,895, entitled, "MULTI-LAYER OPTICAL RECORD" issued to F. W. Spong, on June 27, 1978, an optical disc record/playback system is described wherein data is recorded in the form of pits in an absorbtive coating on the surface of an optical disc. The pits are formed by focusing a high intensity light beam on the surface. In the Spong system, approximately 10.sup.11 bits of information can be stored on one side of a disc-shaped record medium having a 30 cm diameter.
In very high density optical disc systems two turntables, operating independently, may be required to achieve the high data rate continuous operation. In these very high density disc systems, the acceleration and deceleration during fast access may cause interfering vibrations. For example, fast spinup requirements of one turntable may impose a large reaction torque on the frame of the structure which is transmitted via the frame to another turntable or translation stage containing tracking and focus apparatus which is operating simultaneously. In general, this reaction torque may cause loss of track or focus on the working turntable, i.e., the induced vibrations in the working turntable or its associated equipment may adversely affect the system operation. Further, the translational stage which is used in radially positioning the optical head of an optical disc recorder/player may effect vibration in the system. In certain applications, e.g., wherein several optical heads associated with a single disc are independently controlled in time and space, a problem may exist whereby one of the optical heads and its associated translational stage which is undergoing high acceleration or deceleration in achieving fast access disturbs another optical head or its associated translational stage while reading or writing on the same or on another disc. Large inertial forces transmitted via the frame of the system may disturb the reading optical head. Furthermore, the focus actuator in one optical head may impose relatively large reaction forces on the translation stage upon which it is mounted or on an optical head. Due to the compliance of the translational stage, linear and rotary vibrations may detract from tracking and focus performance. For example, the linear vibration of the focus actuator housing may couple to the tracking galvanometer, producing rotary vibration of the tracking galvanometer shaft in the presence of the galvanometer rotating assembly unbalance.